Single point mutations of at least one of the RAS genes (KRAS, HRAS, and NRAS) are found in many human cancers, particularly in colon, lung and pancreatic cancer. RAS mutations are most commonly found in KRAS (about 85%), less commonly in NRAS (about 12%) and rarely in HRAS (about 3%). KRAS encodes two splice variants, A and B, with divergent C-terminal sequences due to the alternate utilization of exon 4. Mutant KRAS (mut-KRAS) may be present in up to about 25% of all human tumors. Mut-KRAS may play a critical role in driving tumor growth and resistance to therapy. An agent with even a modest effect on mut-KRAS activity, or one that exhibits selective inhibition of a subset of mut-RAS could have a major impact on therapy, and decrease cancer patient suffering and morbidity. Thus, finding new agents that inhibit the growth of mut-KRAS tumors is desirable.